Mine have been very stable, more so since abandoning WiFi and going to Ethernet. They're running a full desktop OS (Ubuntu Mate). You can find it here. I use x11VNC to view/control them.
Though I must say, since having to learn how to use SSH and command line BOINC with a few other SBCs, I do prefer it and I won't bother with a full desktop on any new machines I get my hands on.
I tried ubuntu mate as well, but had the same problems just after a few hours. Yesterday I switched to Arch Linux, maybe I will have more luck with it. It this is unstable as well, maybe there is something wrong with my Odroid? : /